GOALI/FRG: The Oxidation of Silicon Carbide and Structure-Defects-Mobility Relations

Vanderbilt University, Nashville TN

Investigators

Abstract

NON-TECHNICAL ABSTRACT Silicon-based electronic devices are the main component in virtually all microelectronic applications, e.g., computers and computer chips that are everywhere in cars, appliances, etc. For high-power and high-temperature uses, however, e.g., on-engine chips, power grid controls, etc. Si-based electronics are either inefficient or not usable at all. Silicon carbide is the most promising alternative, but, despite major advances in the last decade, including breakthroughs by the present team, difficult technical problems remain to be resolved. The proposed research addresses these issues with a mix of experimental and theoretical techniques. At the heart of the difficulties is the interface between silicon carbide and its native oxide, namely silicon dioxide, and the impact of the oxidation process on the underlying crystalline material. The expected results will be relevant to the broader field of the oxidation of diverse materials. Educational outreach projects will highlight to high school teachers and students the special needs of high-power, high-temperature electronics and the impact of research advances in important applications. TECHNICAL ABSTRACT Silicon carbide is a promising alternative to Si for high-temperature, high-power electronics because of its larger energy gap and heat-conduction coefficient, but also because its native oxide is silicon dioxide. The SiC/SiO2 interface, however, is more complex that the Si/SiO2 interface, which is at the heart of Si-based electronics. The main problem is that oxidation releases C atoms, some of which are stuck at the interface as defects. Despite major advances in passivating defects at the SiC/SiO2 by N and H, including breakthroughs by the present team, electron mobility remains lower than desirable for applications. Recent evidence points to subtle changes in the underlying SiC substrate. The proposed research will combine state-of-the-art microscopy, electrical measurements, and theory to elucidate the oxidation process at the atomic scale, identify the origins of undesirable effects and defects, and identify new design specifications to improve carrier mobilities. Extensive education outreach will make advances accessible to high schools and the community.